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Scott Ingram <[log in to unmask]>
Mon, 22 Nov 1999 16:03:11 -0500
text/plain (30 lines)
So then, [log in to unmask] says this:
> [log in to unmask] wrote:
> >Some sort of automation controls the rail operations of the DC metro while
> >an operator rides aboard the train to open the doors and announce the stops.
> >However, the operators have been running the trains manually for the past
> >few months as they have encountered several problems with the automatic
> >system.  I believe that it comes from the mid-seventies, so it was long
> >before Ada's time.
> Considering that the mechanism seems to have "worn out", I presume the
> problems are hardware rather than software, and thus Ada would not have
> been even close to a magic bullet.

Indeed, the problems are (almost) hardware, but in truth seem to be a typical
DC management snafu.

Its actually even worse than Michael's original description:  The automatic
relays used in the control system were damaged by negligent/improper cleaning.
The relays in question are only 3-4 years old in most cases, and the relay
manufacturer has disclaimed responsibility for any liability because there is
no accurate record of which relays were improperly maintained and which were
properly cleaned.  (I question the overall reliability of any heavy equipment
control relay that must have its contacts cleaned with bond paper...)

Scott Ingram
Sonar Processing and Analysis Laboratory
Johns Hopkins University Applied Physics Laboratory